The practice of laser isotope enrichment is in part exemplified in U.S. Pat. Nos. 3,772,519 and 3,939,354, and in United States patent application of P. G. DeBaryshe et al, entitled SYSTEM FOR ILLUMINATING A REGION FOR ISOTOPICALLY SELECTIVE PHOTOEXCITATION, filed herewith, all commonly assigned and incorporated herein by reference. In the practice there shown, it is desirable to illuminate a vapor environment, typically of uranium, with multiple traversals of radiation. The radiation may or may not overlap between different traversals to a significant degree.
Substantial overlap would bring the benefit of increased intensity of the radiation within the illuminated area as well as more uniform and homogeneous utilization of the energy in the beam within the illuminated region, thereby reducing path length. In the extreme, it would be desirable to have complete overlap from traversal to traversal. Such a condition, however, would make difficult or impossible the initial injection of the radiation into the region as well as its recovery after a predetermined number of traversals.